The present invention relates to an elevator shaft closure, which is preferably used for elevator installations with fire protection requirements as are demanded in known Standards such as BS476, UL10B or DIN4102.
The elevator shaft closure enables access from the floor to the car. It consists of the principal parts of a door frame and at least one door leaf. The door frame is alternatively connected, depending on the type of building, directly with a wall or on a foundation frame. At least one door leaf is slidably mounted in the door frame. Depending on the possible forms of arrangement of the door leaves distinction is then made between single-leaf or multi-leaf telescopic doors or center doors. Telescopic doors close and open on one side, whereas center doors open and close at both sides from or towards the center or middle of the door opening.
In the case of the closed elevator shaft closure with telescopic doors, the closing-side door leaf together with the closing-side door frame forms a closing edge region. The closing edge region is usually formed as a labyrinth, as is described in, for example, the transcript of the “Vereinigung der Technischen Überwachungsvereine” expert committee of the 12th sitting of May 5, 1999 (Berlin).
In this elevator shaft closure the problem is of distortion of the closing-side door frame when acted on, in accordance with the Standard, by fire and the thereby defined thermal stress. This distortion has the consequence that the closing-side door leaf is forced away and consequently a larger gap, which is not acceptable according to the Standard, results. In the Standard requirement according to BS476, part 20 (Integrity), for example, a permissible maximum gap size of 6 millimeters is defined.
Usual present-day solutions counteract this distortion and the resulting forcing away of the door leaf by the closing-side door frame being connected by stiff connecting supports with the wall or by the labyrinth depth being formed to be appropriately deep, partly greater than 35 millimeters. These solutions are expensive in production and assembly or they have a non-aesthetic effect.
UK patent document GB-A-2352754 shows a smoke sealing element in the form of brushes which seal the gap between the door leaf and the door frame. The object of this gap seal is to prevent propagation of cooled down smoke in the building. This solution fails in the case of direct exposure of the elevator doors to flame, as is given in the case of fire in the immediate vicinity of the access to the elevator shaft closure. The brushes melt or burn away and the elevator shaft closure is deformed under the influence of thermal loading in such a manner that large door gaps arise, whereby the risk of fire propagation in the elevator shaft and thus also in other floors is increased.